The Blackhawk's newest weapon, a manned torpedo, is commandeered by Octo and his gang with Blackhawk inside. A race of mermen attack Octo's mechanical octopus and eventually Blackhawk is freed.
Hendrickson is expelled from the team because he fails their regular proficiency tests. He is captured by Manta Ray and used to lure the Blackhawks into a trap, but escapes and saves everyone, which qualifies him for readmission.